The present invention relates to a handheld electric eater-mixer, particularly a household beater-mixer, adapted to drive selectively at least one so-called beating accessory such as, for example, a whisk, or a so-called mixing accessory turning at high speed such as, for example, a mixing foot, and comprising a body containing an electric drive motor, two rotatable coupling devices connected to the shaft of the motor and adapted to receive, via respectively two engagement passages opening into the body, the beating accessory and, respectively, the mixing accessory, and a control switch for the electric motor which is actuated by an actuating finger piece mounted rotatably on a rotation axle so as to occupy a stop position in several switched positions for continuous operation of the motor.
There is meant by beating accessory a working tool of the whisk or kneading type, and by mixing accessory a working tool turning at high speed of the mixing foot type with a rotatable knife.
In a known apparatus of this type, the actuating finger piece is adapted to control the same control switch for continuous operation of the motor, not only in case of use of the beating accessory but also in the case of the mixing accessory; in these two cases of use, the actuating finger piece is locked in each of its switched positions, permitting the continuous operation of the motor. However, in the presence of the mixing accessory whose working tool of the knife type is adapted to turn at high speed, it can happen that the apparatus in use slides from the hand of the user; in this case, because the actuating finger piece remains locked in switched position, the apparatus continues to run and because of this, the moving working tool risks exposing the user to serious wounding.
The invention has particularly for its object to eliminate this risk and to provide an electric handheld beater-mixer of the type set forth above, which has increased safety of operation in continuous use of the motor when it is more particularly provided with the mixing accessory.
According to the invention, a spiral spring is mounted concentrically to the rotational axle of the actuating finger piece and has a so-called fixed end which is connected to said actuating finger piece and a so-called free end, and the apparatus moreover comprises a safety member having a portion forming an abutment and mounted movably in the body between a rest position in which the mixing accessory is inserted in its coupling device and in which the free end of the spring rests on the portion forming an abutment for said safety member such that the spring will be permanently in tension when the actuating finger piece occupies each of its switched positions, such that the actuating finger piece is held in its switched position by the hand of an operator against the force of the spring, and a retracted position into which it is thereafter brought by the insertion of the beating accessory in its coupling device and in which its portion forming a bearing is removed relative to the free end of the spring such that the spring will be permanently released from tension when the actuating finger piece occupies each of its switched positions in which said finger piece is held in place by the help of mechanical retention means disposed in the body, said safety member returning automatically to the rest position after withdrawal of the beating accessory.
Thanks to this retractable safety member permitting permanently tensioning the spiral spring connected to the actuating finger piece during continuous operation of the motor in the presence of the mixing accessory, it will be understood that the finger piece will return automatically to the stop position under the action of the spring if the apparatus slides from the hand of the user. Moreover, this safety member constitutes by itself a member adapted to detect either the presence of the mixing accessory, the actuating finger piece of the switch in the position of continuous operation being held by the hand, or the presence of the beating accessory, the actuating finger piece of the switch in the continuous operating position being locked.